Mark Kermode considers the business of showing films in the last of three programmes.

The route from script to finance to screen can be a long one - but then it all comes down to one nervous opening weekend.

Marketing may convince us of a film's merit but, one comment on social media can ruin even the most inventive campaign.Film festivals are vital for launching a film. The Autumn festival season is where artistic creators battle for the first showing of the most talked about films. For many independent film makers exposure through awards is seen as a crucial - or perhaps only - means of survival. The artistic director of the Toronto Film festival reveals how film makers plead with him to admit their films.The decline in DVD sales has led to nearly a halving of studio profits. Vincent Bruzzese runs a research entertainment firm and believes there is a disconnect between the film makers and the audience. By analysing data, it's possible to work out why a certain scene works. Hit on certain story tropes and a film will do well.Netflix and Amazon's are all about giving customers what they want. Their algorithms are set to challenge the studios' dominance. How long is it until the streaming services become major studios themselves?

Meanwhile, the growth of cinema multiplexes have paved the way for boutique cinemas and the notion of the film as an event. Audiences today are engaging with films in very different ways, so how do UK cinemas make most of their money?Producers: Barney Rowntree and Nick Jones

A Hidden Flack production for BBC Radio 4, first broadcast in March 2015.